1. Field of the Invention
The present invention relates to a steering control apparatus for a vehicle that recognizes travel partitioning lines on a road based on images obtained by photography using a camera, and performs steering control such that the vehicle travels along the travel partitioning lines.
2. Description of the Related Art
Conventionally, as in the steering control apparatus for a vehicle disclosed in Japanese Unexamined Patent Application, First Publication No. 2001-10519, a steering control apparatus for a vehicle is known that, by performing image processing on images obtained from a vehicle-mounted camera that photographs a travel route, detects lines on the road (for example, travel partitioning lines such as white lines) and provides assistance to the steering torque input by a driver such that the vehicle is made to travel along these lines.
In this steering control apparatus for a vehicle settings are made such that, based on the amount of change in the steering torque input by the driver and on an amount of lateral slippage from a line on the road to the vehicle position, it is determined whether the driver is performing the driving action intentionally. Moreover, in accordance with the result of the determination as to whether the driving action is intentional, it is decided whether it is possible to output a warning or to provide assistance to the steering torque.
However, in a steering control apparatus for a vehicle according to the above related art, when calculating the amount of change in the steering torque input by the driver, firstly, measurement of the temporal change in the steering torque over a predetermined sampling period (for example, over several seconds) is started, and whether the driving action is intentional is determined after the temporal change amount in the steering torque within this sampling period has been calculated. Therefore, the problem exists that it is not possible to determine whether the driving action is intentional during this sampling period. Namely, if the time required to determine whether the driver is driving intentionally is lengthened, then the concern arises that appropriate steering control that corresponds to the intention of the driver cannot be performed during the period that this determination processing is continuing.
The present invention was conceived in view of the above circumstances and it is an object thereof to provide a steering control apparatus for a vehicle that enables appropriate steering control to be performed by rapidly and accurately determining whether a driver is intentionally performing a driving action when performing steering control such that a vehicle travels along recognized travel partitioning lines.
In order to solve the above problems and achieve the objects of the present invention, the first aspect of the present invention is a steering control apparatus for a vehicle, comprising: an actuator (for example, the motor 20 in the embodiment described below) that drives a steering mechanism (for example, the manual steering power generating mechanism 16 in the embodiment described below) capable of steering wheels (for example, the steering wheels 19 and 19 in the embodiment described below) of the vehicle; a torque detector (for example, the torque sensor 22 in the embodiment described below) that detects steering torque input by a driver; a travel route recognizing section (for example, the camera 25 and the image recognition processing section 26 in the embodiment described below) that recognizes a travel route of the vehicle; and a steering assistance section (for example, the EPS control apparatus 24 in the embodiment described below) that outputs a signal that drives the actuator such that the vehicle travels along the travel route recognized by the travel route recognizing section, wherein the steering control apparatus for a vehicle is provided with: a steering torque change state calculation section (for example, step S04 in the embodiment described below) that calculates one of a moving integral value of an amount of change in the steering torque detected by the torque detector and a moving integral value of a squared value of an amount of change in the steering torque detected by the torque detector; a driving intention determination section (for example, steps S05 to S10 in the embodiment described below) that determines whether there has been a decrease in the driving intention of the driver based on a result of a calculation by the steering torque change state calculation section; a notification section (for example, the warning apparatus 34 in the embodiment described below) that outputs a warning to the driver; and an execution section (for example, the LKAS control apparatus 23 in the embodiment described below) that executes at least one of stopping the driving of the actuator by the steering assistance section and outputting the warning by the notification section when it is determined by the driving intention determination section that there has been a decrease in the driving intention.
According to the steering control apparatus for a vehicle having the above structure, for example, in a processing sequence that is executed at regular predetermined intervals, the steering torque change state calculation section calculates the absolute value of the difference between the previous value of the steering torque from the previous processing that was detected by the torque detector and the current value of the steering torque in the current processing that is detected by the torque detector, and stores each one as time series data. The driving intention determination section determines whether there has been a decrease in the driving intention of the driver in accordance with a moving integral value that is obtained by adding absolute values of the above differences or squared values of the above differences that have been stored for a predetermined number of times in the past up until the current processing.
Namely, it is possible to calculate a moving integral value of an amount of change in the steering torque detected by the torque detector, or to calculate a moving integral value of the squared value of the amount of change in the steering torque simply by using straightforward and rapid processing that entails simply adding a new data calculated in the current processing to the time series data for the past stored previously. In addition, it is possible to determine immediately whether there has been a decrease in the driving intention of the driver based on these moving integral values. Furthermore, it is possible to determine simply and accurately whether there has been a decrease in the driving intention of the driver.
Moreover, in the steering control apparatus for a vehicle of the present invention, the driving intention determination section may determine that there has been a decrease in the driving intention when a state in which the result of a calculation by the steering torque change state calculation section is less than or equal to a predetermined value continues for a predetermined time or longer.
According to the steering control apparatus for a vehicle having the above described structure, the driving intention determination section does not determine that there has been a decrease in the driving intention simply when the result of a calculation by the steering torque change state calculation section is equal to or less than a predetermined value, but makes this determination when this state has continued over a predetermined time or longer. As a result, it is possible to reliably determine whether there has been a decrease in the driving intention, and to perform even more appropriate steering control.
The second aspect of the present invention is a steering control apparatus for a vehicle, comprising: an actuator (for example, the motor 20 in the embodiment described below) that drives a steering mechanism (for example, the manual steering power generating mechanism 16 in the embodiment described below) capable of steering wheels (for example, the steering wheels 19 and 19 in the embodiment described below) of the vehicle; a torque detector (for example, the torque sensor 22 in the embodiment described below) that detects steering torque input by a driver; a travel route recognizing section (for example, the camera 25 and the image recognition processing section 26 in the embodiment described below) that recognizes a travel route of the vehicle; and a steering assistance section (for example, the EPS control apparatus 24 in the embodiment described below) that outputs a signal that drives the actuator such that the vehicle travels along the travel route recognized by the travel route recognizing section, wherein the steering control apparatus for a vehicle is provided with: a steering torque difference calculation section (for example, step S45 in the embodiment described below) that calculates a difference between a maximum value and a minimum value in a predetermined period of the steering torque detected by the torque detector; a driving intention determination section (for example, steps S46 to S49 and steps S09 and S10 in the embodiment described below) that determines whether there has been a decrease in the driving intention of the driver based on a result of a calculation by the steering torque difference calculation section; a notification section (for example, the warning apparatus 34 in the embodiment described below) that outputs a warning to the driver; and an execution section (for example, the LKAS control apparatus 23 in the embodiment described below) that executes at least one of stopping the driving of the actuator by the steering assistance section and outputting the warning by the notification section when it is determined by the driving intention determination section that there has been a decrease in the driving intention.
According to the steering control apparatus for a vehicle having the above described structure, for example, in a processing sequence that is executed at regular predetermined intervals, the steering torque difference calculation section sets the values of the steering torque detected by the torque detector as time series data, extracts the maximum value and minimum value of the steering torque over a predetermined time, and calculates the difference between this maximum value and minimum value. The driving intention determination section then determines whether there is a decrease in the driving intention in accordance with this difference between the maximum value and minimum value. In this case, it is possible to quantitatively determine whether there is a decrease in the driving intention using statistical processing. Moreover, it is possible to determine simply and accurately whether there is a decrease in the driving intention.
Moreover, in the steering control apparatus for a vehicle of the present invention, the driving intention determination section may determine that there has been a decrease in the driving intention when a state in which the result of a calculation by the steering torque difference calculation section is less than or equal to a predetermined value continues for a predetermined time or longer.
According to the steering control apparatus for a vehicle having the above described structure, the driving intention determination section does not determine that there has been a decrease in the driving intention simply when the result of a calculation by the steering torque difference calculation section is equal to or less than a predetermined value, but makes this determination when this state has continued for a predetermined time or longer. As a result, it is possible to reliably determine whether there has been a decrease in the driving intention, and to perform even more appropriate steering control.
Moreover, in the steering control apparatus for a vehicle of the present invention, the driving intention determination section may determine that there has been a decrease in the driving intention when, in addition to the result of the calculation by the steering torque difference calculation section, a state in which the steering torque detected by the torque detector is less than or equal to a predetermined value continues for a predetermined time or longer.
According to the steering control apparatus for a vehicle having the above described structure, the driving intention determination section determines that there has been a decrease in the driving intention when, in addition to the result of the calculation by the steering torque difference calculation section, a state in which the steering torque detected by the torque detector is less than or equal to a predetermined value continues for a predetermined time or longer. As a result, it is possible to reliably determine whether there has been a decrease in the driving intention, and to perform even more appropriate steering control.
Furthermore, the third aspect of the present invention is a steering control apparatus for a vehicle, comprising: an actuator (for example, the motor 20 in the embodiment described below) that drives a steering mechanism (for example, the manual steering power generating mechanism 16 in the embodiment described below) capable of steering wheels (for example, the steering wheels 19 and 19 in the embodiment described below) of the vehicle; a torque detector (for example, the torque sensor 22 in the embodiment described below) that detects steering torque input by a driver; a travel route recognizing section (for example, the camera 25 and the image recognition processing section 26 in the embodiment described below) that recognizes a travel route of the vehicle; and a steering assistance section (for example, the EPS control apparatus 24 in the embodiment described below) that outputs a signal that drives the actuator such that the vehicle travels along the travel route recognized by the travel route recognizing section, wherein the steering control apparatus for a vehicle is provided with: a steering torque change state calculation section (for example, step S04 in the embodiment described below) that calculates one of a moving integral value of an amount of change in the steering torque detected by the torque detector and a moving integral value of a squared value of an amount of change in the steering torque detected by the torque detector; a steering torque difference calculation section (for example, step S45 in the embodiment described below) that calculates a difference between a maximum value and a minimum value of the steering torque detected by the torque detector in a predetermined period; a first driving intention determination section (for example, steps S05 to S10 in the embodiment described below) that determines whether there has been a decrease in the driving intention of the driver based on a result of a calculation by the steering torque change state calculation section; a second driving intention determination section (for example, steps S46 to S49 and steps S09 and S10 in the embodiment described below) that determines whether there has been a decrease in the driving intention of the driver based on a result of a calculation by the steering torque difference calculation section; a driving intention determination section (for example, a determination processing step in the embodiment described below) that determines whether there has been a decrease in the driving intention in accordance with at least the determination result by either of the first or second driving intention determination sections; a notification section (for example, the warning apparatus 34 in the embodiment described below) that outputs a warning to the driver; and an execution section (for example, the LKAS control apparatus 23 in the embodiment described below) that executes at least one of stopping the driving of the actuator by the steering assistance section and outputting the warning by the notification section when it is determined by the driving intention determination section that there has been a decrease in the driving intention.
According to the steering control apparatus for a vehicle having the above structure, for example, in a processing sequence that is executed at regular predetermined intervals, the steering torque change state calculation section calculates the absolute value of the difference between the previous value of the steering torque from the previous processing that was detected by the torque detector and the current value of the steering torque in the current processing that is detected by the torque detector, and stores each one as time series data. The first driving intention determination section determines whether there has been a decrease in the driving intention of the driver in accordance with a moving integral value that is obtained by adding absolute values of the above differences or squared values of the above differences that have been stored for a predetermined number of times in the past up until the current processing. Furthermore, for example, in a processing sequence that is executed at regular predetermined intervals, the steering torque difference calculation section sets the values of the steering torque detected by the torque detector as time series data, extracts the maximum value and minimum value of the steering torque over a predetermined time, and calculates the difference between this maximum value and minimum value. The second driving intention determination section then determines whether there is a decrease in the driving intention in accordance with this difference between the maximum value and minimum value. The execution section then executes at least one of stopping the driving of the actuator and outputting the warning based on at least the determination result by either of the first or second driving intention determination sections. Because of this, it is possible to improve the flexibility of the determination when determining the driving intention.
Moreover, in the steering control apparatus for a vehicle of the present invention the first driving intention determination section may determine that there has been a decrease in the driving intention when a state in which the result of a calculation by the steering torque change state calculation section is less than or equal to a first predetermined value continues for a first predetermined time or longer, and the second driving intention determination section determines that there has been a decrease in the driving intention when a state in which the result of a calculation by the steering torque difference calculation section is less than or equal to a second predetermined value continues for a second predetermined time or longer.
According to the steering control apparatus for a vehicle having the above described structure, it is not determined that there has been a decrease in the driving intention simply when the result of a calculation by the steering torque change state calculation section or by the steering torque difference calculation section is equal to or less than a predetermined value, but this determination is made when these states have continued for a predetermined time or longer. As a result, it is possible to reliably determine whether there has been a decrease in the driving intention, and to perform even more appropriate steering control.
Furthermore, the fourth aspect of the present invention is a steering control apparatus for a vehicle, comprising: an actuator (for example, the motor 20 in the embodiment described below) that drives a steering mechanism (for example, the manual steering power generating mechanism 16 in the embodiment described below) capable of steering wheels (for example, the steering wheels 19 and 19 in the embodiment described below) of the vehicle; a torque detector (for example, the torque sensor 22 in the embodiment described below) that detects steering torque input by a driver; a travel route recognizing section (for example, the camera 25 and the image recognition processing section 26 in the embodiment described below) that recognizes a travel route of the vehicle; and a steering assistance section (for example, the EPS control apparatus 24 in the embodiment described below) that outputs a signal that drives the actuator such that the vehicle travels along the travel route recognized by the travel route recognizing section, wherein the steering control apparatus for a vehicle is provided with: a standard deviation calculation section (for example, the standard deviation determining step in the embodiment described below) that calculates any of a standard deviation in the steering torques detected by the torque detector and a standard deviation in change amounts of the steering torque; a driving intention determination section (for example, the standard deviation determination step and steps S47 to S49 and steps S09 and S10 in the embodiment described below) that determines whether there has been a decrease in the driving intention of the driver based on a result of a calculation by the standard deviation calculation section; a notification section (for example, the warning apparatus 34 in the embodiment described below) that outputs a warning to the driver; and an execution section (for example, the LKAS control apparatus 23 in the embodiment described below) that executes at least one of stopping the driving of the actuator by the steering assistance section and outputting the warning by the notification section when it is determined by the driving intention determination section that there has been a decrease in the driving intention.
According to the steering control apparatus for a vehicle having the above structure, for example, in a processing sequence that is executed at regular predetermined intervals, the standard deviation calculation section sets steering torque values detected by the torque detector as time series data, and calculates one of the standard deviation or the standard deviation in the amounts of change in the steering torque. The driving intention determination section then determines whether there has been a decrease in the driving intention in accordance with one of the calculated standard deviation or standard deviation in the amounts of change in the steering torque. As a result, it is possible to determine simply and accurately whether there is a decrease in the driving intention.
Moreover, in the steering control apparatus for a vehicle of the present invention the driving intention determination section may determine that there has been a decrease in the driving intention when a state in which the result of the calculation by the standard deviation calculation section is less than or equal to a predetermined value continues for a predetermined time or longer.
According to the steering control apparatus for a vehicle having the above described structure, the driving intention determination section does not determine that there has been a decrease in the driving intention simply when the result of a calculation by the standard deviation calculation section is equal to or less than a predetermined value, but makes this determination when this state has continued for a predetermined time or longer. As a result, it is possible to reliably determine whether there has been a decrease in the driving intention, and to perform even more appropriate steering control.
Moreover, in the steering control apparatus for a vehicle of the present invention there may be provided a determination section (for example, the standard deviation determination step in the embodiment described below) for determining whether a size of the steering torque detected by the torque detector is less than or equal to a predetermined value, and the driving intention determination section may determine that there has been a decrease in the driving intention when the size of the steering torque in the result of the determination by the determination section is less than or equal to a predetermined value, and the result of the calculation by the standard deviation calculation section is less than or equal to a predetermined value.
According to the steering control apparatus for a vehicle having the above described structure, the driving intention determination section does not determine that there has been a decrease in the driving intention simply when the result of a calculation by the standard deviation calculation section is equal to or less than a predetermined value, but makes this determination when the size of the steering torque is equal to or less than a predetermined value. As a result, it is possible to reliably determine whether there has been a decrease in the driving intention, and to perform even more appropriate steering control.
Moreover, in the steering control apparatus for a vehicle of the present invention, the execution section may output the warning over a predetermined time from when it is determined by the driving intention determination section that there has been a decrease in the driving intention.
According to the steering control apparatus for a vehicle having the above described structure, if it is determined by the driving intention determination section that there has been a decrease in the driving intention, then it is possible to call the driver""s attention to this by outputting a warning for a predetermined time from when the above determination is made using a notification section formed, for example, by a speaker that outputs a warning noise or a voice message or, for example, by a display that displays a warning or a lamp that flashes on or the like.
Moreover, in the steering control apparatus for a vehicle of the present invention, the execution section may stop the driving of the actuator motor after the output of the warning by the notification section.
According to the steering control apparatus for a vehicle having the above described structure, if it is determined by the driving intention determination section that there has been a decrease in the driving intention, firstly, the driver""s attention is called by outputting a warning for a predetermined time using the notification section. Thereafter, if it is determined while this warning is being output that this decrease in the driving intention is still continuing, then it is determined that it is an inappropriate state for continuing the steering control, and the driving of the actuator is halted.
As a result, it is possible to reliably determine whether it is an appropriate state for continuing the steering control, and it is possible to prevent the driving of the actuator and the stopping of the driving of the actuator from being executed easily, thereby enabling suitable steering control to be performed.
Moreover, in the steering control apparatus for a vehicle of the present invention, after the driving of the actuator has been stopped, the driving of the actuator may be recommenced when it is determined by the driving intention determination section that there has been no decrease in the driving intention.
According to the steering control apparatus for a vehicle having the above described structure, after the driving of the actuator has been stopped, when, for example, a calculation result that exceeds a predetermined value is obtained in the steering torque change state calculation section, or the steering torque difference calculation section, or the standard deviation calculation section, it is determined by the driving intention determination section that there has been no decrease in the driving intention and the driving of the actuator is resumed. As a result, it is possible to perform appropriate steering control in accordance with the condition of the driver.
Moreover, in the steering control apparatus for a vehicle of the present invention, the driving intention determination section may determine whether there has been a decrease in the driving intention after a predetermined time has passed from when the driving of the actuator was stopped.
According to the steering control apparatus for a vehicle having the above described structure, it is not immediately determined by the driving intention determination section whether there has been a decrease in the driving intention, even when, for example, a calculation result that exceeds a predetermined value is obtained in the steering torque change state calculation section, or the steering torque difference calculation section, or the standard deviation calculation section after the driving of the actuator has been stopped. Instead, a determination as to whether there has been a decrease in the driving intention is made by the driving intention determination section, after a predetermined time has lapsed from when the driving of the actuator was stopped. As a result, particularly when the driving of the actuator is resumed, it is possible to reliably determine that there has been no decrease in the driving intention, and it is possible to prevent the driving of the actuator and the stopping of the driving of the actuator from being executed easily, thereby enabling suitable steering control to be performed.
Furthermore, in the steering control apparatus for a vehicle of the present invention, there may be provided with a deviation warning notification section (this role may also be performed, for example, by the LKAS control section 23 in the embodiment described below) that recognizes a position of the vehicle in the widthwise direction on the travel route based on a result of a recognition made by the travel route recognizing section, and when the position of the vehicle reaches a predetermined reference position (for example, the deviation warning commencement threshold value TH2 in the embodiment described below) that shows a deviation from the travel route, the deviation warning notification section determines that a possibility exists that the vehicle has deviated from the travel route and outputs a deviation warning, and wherein when it is determined by the driving intention determination section that there has been a decrease in the driving intention, the deviation warning notification section alters the reference position such that it is frequently determined that a possibility exists that the vehicle has deviated from the travel route.
According to the steering control apparatus for a vehicle having the above described structure, when the position of the vehicle is further from a travel partitioning line on the travel route that is recognized by the travel route recognizing section than a predetermined reference position, the deviation warning notification section determines that a possibility exists that the vehicle has deviated from the travel route. At this time, the deviation determination section alters the reference position based on the result of a determination in the driving intention determination section, and by reflecting a decrease or otherwise in the driving intention in the setting of the reference position, it is possible to perform the appropriate deviation determination in accordance with the driving state of the driver.